JP4795155B2 - Optical device, imaging device, and control method thereof - Google Patents

Description

  The present invention relates to an optical apparatus having an automatic focus detection function, an imaging apparatus, and a control method thereof.

  Conventionally, when a shutter button is pressed in the still image shooting mode, it has been proposed to present a focus determination result to a user using sound or display. For example, Patent Document 1 proposes a focus position detection device that can confirm where the focus position is on the screen on the viewfinder. In this proposal, the block corresponding to the in-focus position is determined from the high-frequency component for each block of the image signals for two screens, and the display of the block corresponding to the in-focus position on the viewfinder screen is blinked from this determination result. It is like that. Further, for example, Patent Document 2 discloses an imaging device with an indicator that informs the user of the degree of focus as needed. In this proposal, the degree of focus of an image received through the imaging lens is quantitatively calculated, and information about the degree of focus is notified to the user by screen display or voice.

  In recent years, in order to perform focus control with high speed and high accuracy, a hybrid AF method using a combination of a TV-AF method and a focus detection method other than the TV-AF method (for example, an AF method based on a phase difference) has been developed. Proposed. The TV-AF system here refers to extracting a high-frequency component (AF evaluation value) from a video signal obtained by photoelectrically converting a subject image with an image sensor by a band-pass filter in a certain band, and the AF evaluation value is maximum. The focus lens is moved and controlled so that the focus is adjusted. In the AF method based on the phase difference, the light beam received from the subject is divided into two parts, each of the two divided light beams is received by a set of focus detection sensors, and the amount of deviation of the image output according to the amount of received light is determined. By detecting, the subject distance is obtained by triangulation.

In such a hybrid AF method, detection target areas such as a distance measurement area or a focus detection area of each AF method may be different. Thus, an electronic camera has been proposed that can easily focus on a desired subject part by notifying a user of a detection target region and a focus determination result when the shutter button is pressed (for example, a patent) Reference 3).
JP-A-6-205258 JP 2004-333828 A JP 2002-311328 A

  However, in the conventional TV-AF method, the focus lens is repeatedly inverted and moved so that the AF evaluation value becomes maximum. Then, it is determined that the focus is achieved when the reverse movement continues. For this reason, it takes too much time to present that the subject is in focus, which may cause discomfort to the user.

  This is particularly noticeable in the hybrid AF method of Patent Document 3 described above. That is, the AF method based on the phase difference is performed, and the focus is adjusted with high accuracy by the TV-AF method after the focus reaches the vicinity of the in-focus position. Therefore, it takes time until the focus is determined after the AF method based on the phase difference is almost focused. Then, if the user is informed that the in-focus state is obtained, the user may feel uncomfortable.

  Therefore, the present invention has been made in view of the above-described problems, and an object thereof is to further improve the convenience of the function of notifying the user that the focus has been achieved.

In order to solve the above-described problem, as a technical feature of the present invention, an optical apparatus including an imaging unit that outputs an image according to subject light, and a display control unit that controls to display the image on a display unit. In this control method, after the first position which is the in- focus position by the first focus detection means is detected , the focus lens is moved to the first position at the first speed, and the first speed is detected. The focus lens is moved at a second speed that is lower than the second speed, and control is performed so as to detect the second position that is the in- focus position by the second focus detection means. After the focus lens is moved to the first position at the first speed when the first position is detected, and before the focus lens is moved at the second speed Information that can be identified as in-focus And controlling to perform output for notifying the user.

Another technical feature of the present invention is a method of controlling an optical device having an imaging unit that outputs an image in accordance with subject light and a display control unit that controls the display unit to display the image. The first position is detected after detecting the first position, which is the in- focus position corresponding to the output from the second focus detection means, which is less accurate than the first focus detection means for detecting the focus state of the focus lens. When the first position is detected by the first focus detection means, the first position is controlled so as to detect the second position which is a focus position according to the output from the focus detection means. The focus lens is positioned at a position, and before the focus lens is moved to detect the second position, information that can be identified as being in focus before the focus lens is moved is notified to the user for And controlling to perform a force.

  ADVANTAGE OF THE INVENTION According to this invention, the information which can identify the state which focused is provided without giving a sense of incongruity to a user.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows the configuration of a video camera (imaging device) that is one embodiment of the present invention. Hereinafter, in this embodiment, a video camera integrated with a photographing lens will be described, but the present invention can also be applied to a video camera in which a photographing lens can be attached. In this case, a control signal generated by a camera / AF microcomputer, which will be described later, is communicated to the microcomputer in the photographing lens, and the camera / AF microcomputer controls the movement of the focus lens unit via the lens microcomputer. . In this embodiment, a video camera is described, but the present invention can also be applied to various imaging devices such as a digital still camera. The same applies to Example 2 described later.

  In FIG. 1, reference numeral 101 denotes a first fixed lens unit (a fixed first group lens). Reference numeral 102 denotes a lens unit that performs zooming (hereinafter referred to as a zoom lens or a zooming lens). Reference numeral 103 denotes a stop, and reference numeral 104 denotes a second fixed lens unit (a fixed second group lens). Reference numeral 105 denotes a lens unit (hereinafter referred to as a focus lens or focus compensator) that has both a focus adjustment function and a so-called compensator function that corrects image plane movement due to zooming. In the drawing, each lens unit is described as being configured by a single lens, but in actuality, it may be configured by a single lens or by a plurality of lenses. It may be configured. These optical systems are called imaging optical systems.

  The zoom lens 102 and the focus lens 105 are moved in the optical axis direction (left-right direction in FIG. 1) by a zoom motor (zoom drive source) 110 and a focusing motor (focusing drive source) 111, respectively.

  Incident light (subject light) from the subject forms an image on the image sensor 106 through the lens unit and the apertures 101 to 105. The imaging element 106 is a photoelectric conversion element such as a CCD or CMOS sensor, and photoelectrically converts a subject image formed on the imaging surface into an electrical signal. The electrical signal output from the image sensor 106 is sampled and gain adjusted by the CDS / AGC circuit 107 and input to the camera signal processing circuit 108.

  The camera signal processing circuit 108 performs predetermined processing on the signal input from the CDS / AGC circuit 107 and is a video signal suitable for recording and display in the recording unit (recording device) 113 and the monitor unit (monitor device) 109. (Image) is generated. The recording unit 113 records the input video signal on a recording medium (magnetic tape, optical disk, semiconductor memory, etc.) when the photographing / recording start / end switch 117 is pressed. When the photographing / recording start / end switch 117 is pressed again, the recording is ended. The monitor unit 109 displays the subject video on a display such as an electronic viewfinder or a liquid crystal panel based on the input video signal.

  On the other hand, the video signal output of the CDS / AGC circuit 107 is also output to the AF gate 112. The AF gate 112 selects a signal in the screen range used for focus control from the video signal corresponding to the entire screen and outputs it to the AF signal processing circuit (focus detection means) 114. Here, the screen range used for focus control can be arbitrarily set, and a plurality of ranges may be set.

  The AF signal processing circuit 114 uses a high-frequency component used for focus control by the TV-AF method and a luminance difference component generated from the high-frequency signal (difference between the maximum value and the minimum value of the luminance level of the video signal) from the input video signal. AF evaluation values (focus signals) such as are extracted. Then, this is output to the camera / AF microcomputer 115. The AF evaluation value represents the sharpness of an image based on the output signal from the image sensor 106, but the sharpness changes depending on the focus state (focused state) of the image pickup optical system. It is a signal representing the focus state.

  The camera / AF microcomputer 115 searches for the position (focus position) of the focus lens 105 at which the AF evaluation value is at the maximum level (maximum value or a value near it). For this purpose, a control signal is output to the focusing motor 111 to move the focus lens 105 by a predetermined amount (a predetermined amount). This focus control is “TV-AF control”.

  The camera / AF microcomputer 115 controls the entire video camera. The output of the AF signal processing circuit 114 described above and the output of an external distance measuring unit (second detection means) 116, which will be described later, are input to the camera / AF microcomputer 115 and used for AF control calculation. The camera / AF microcomputer 115 outputs a control signal to the focusing motor 111 described above according to the calculation result, and moves the focus lens 105.

  The external distance measuring unit 116 is an external distance measuring method, that is, a sensor of a type that measures a distance to a subject without using light passing through an imaging optical system (photographing lens) and outputs a signal corresponding to the distance. is there. The external distance measuring unit 116 divides the light beam from the subject into two parts, and each set of the two light beams is received by a set of line sensors. Then, the distance to the subject is obtained by the triangulation method by detecting the shift amount of the signal output according to the received light amount, that is, the relative positional shift amount in the beam splitting direction.

  In addition to the passive distance measurement method, the active distance measurement method is often used in a method that obtains the distance from the propagation speed of ultrasonic waves measured using an ultrasonic sensor or a compact camera. Also, there is a triangulation method using infrared rays projected on the subject. However, the detection means is not limited to these distance measuring methods.

  Based on the distance information to the subject (subject distance) detected or measured by the detection signal from the external distance measuring unit 116 and the focal length information of the imaging optical system, the camera / AF microcomputer 115 performs the matching. The position (target position) of the focus lens 105 for obtaining the focus is calculated. Then, the focus lens 105 is moved in the direction of the focus position while acquiring the AF evaluation value. Alternatively, the focus position is read from the table data, and the focus lens 105 is moved in the direction of the focus position while always acquiring the AF evaluation value. The reason why the AF evaluation value is continuously acquired is to change the moving direction of the focus lens when the AF evaluation value starts to decrease. This control method is referred to herein as “external distance measuring AF control”. Here, the focal length information of the imaging optical system can be obtained from an output from a position sensor (not shown) that detects the position of the zoom lens 102 or a drive pulse count value from a reference position of the zoom motor 110.

  Reference numeral 118 denotes a speaker (sound output device).

  Next, hybrid AF control processing performed by the camera / AF microcomputer 115 will be described in detail with reference to FIG. The outline of the hybrid AF control is as follows.

  First, the focus lens is always moved by TV-AF control and moved to the in-focus lens position while searching for the AF evaluation value to be maximized. Therefore, when the subject distance detected by the external ranging AF control changes, the focus lens is moved in the direction of the in-focus position converted from the subject distance detected by the external ranging AF control. Or, when the current focus lens position (operation start position) is far away from the in-focus position, such as when the contrast of the shooting screen changes or when the user changes the subject greatly, the external ranging AF control is used. The focus lens is moved in the direction of the in-focus position. This makes it possible to perform focusing control with high accuracy and at high speed. At this time, the AF evaluation value is continuously acquired, and when the AF evaluation value starts to decrease, the moving direction of the focus lens is changed.

Step 201 indicates the start of control.
Step 202 is TV-AF control. For TV-AF control, the focus lens is moved minutely to perform focusing control (fine adjustment of the focus) at a low speed (slower than a predetermined speed), and the moving amount is larger and faster than the minute operation. There is a hill-climbing operation in which the focus control is performed by moving to (higher than a predetermined speed). This minute operation is also referred to as a minute driving operation in the minute driving mode. The hill-climbing operation is also referred to as a hill-climbing drive operation in the hill-climbing drive mode.

  Step 203 is external measurement AF control. In the external AF control, when the difference between the focus position detected by the external ranging AF control and the current focus lens position is large, a predetermined speed is applied in the direction of the focus position detected by the external ranging AF control. The focus lens is moved faster than this. Note that the difference between the in-focus position detected by the external ranging AF control and the current focus lens position is large when there is a change in the subject distance or when there is a change in the contrast of the shooting screen. .

  Step 204 determines whether or not control by external ranging AF control is performed in the external AF control of Step 203, and moves the focus lens in the direction of the in-focus position detected by external ranging AF control. In the case, the process proceeds to Step 205. When the focus lens is moved by the TV-AF method, the process proceeds to Step 206.

  Step 205 determines whether or not the focus lens has reached the in-focus position detected by the external ranging AF control. When it reaches, it transfers to Step208. Moreover, when it has not reached, it is moved continuously. Although not shown in FIG. 2, when the AF evaluation value starts to decrease during the movement of the focus lens, a process of inverting the movement direction of the focus lens is performed to perform a hill climbing operation, and then go to Step 207 It will be migrated. That is, the TV-AF control is always moving even while the focus lens is being moved to the in-focus position detected by the external ranging AF control.

  Step 206 is a case where focus control is performed in the TV-AF control, and it is determined whether or not focus control is being performed in a hill climbing operation. When focus control is performed by hill climbing operation, the process proceeds to Step 207. If focus control is not performed by hill-climbing operation, the current TV-AF operation (micro operation) is continued as it is.

  In Step 207, when the focus lens is moved by the hill-climbing operation, it is determined whether or not the hill-climbing operation is ended beyond the peak position of the AF evaluation value. When the mountain climbing operation is finished, the process proceeds to Step 208. If the mountain climbing operation is still in progress, the peak position is continuously searched as it is.

  In Step 208, it is determined whether or not shooting recording is in progress. At the time of non-photographing recording, the process proceeds to Step 209, and sound is output from the speaker 118 in order to provide (notify) information that can identify the focused state to the user. Therefore, information that can identify the in-focus state is provided (notified) to the user before the in-focus position is detected by the minute operation.

  Thus, the user is in focus when the focus lens is moved to the in-focus position detected by the external ranging AF control and when the hill-climbing operation is completed when the TV-AF control is performed. Providing information. When the difference between the AF operation start position or current position and the in-focus position obtained by the AF operation is equal to or greater than a predetermined value, the user can be notified of information that can identify the in-focus state. It will be good.

  Also, when focus control based on external ranging AF control is not performed, such as when the in-focus position cannot be detected by external ranging AF control, the shooting screen is focused from the out-of-focus state by TV-AF control. Even when information is not provided to the user even though the state has been changed, the user feels uncomfortable. This is because there is no difference to the fact that the user is in focus. Therefore, it is necessary to provide information even when TV-AF control is performed.

  In the TV-AF control, there are a minute operation and a mountain climbing operation as described above. The minute operation is an operation in the vicinity of the in-focus state, and is a state in which the focus lens is moved while repeating the direction inversion and it is determined whether or not the in-focus state is achieved. That is, in order to detect the in-focus position in the minute operation, the reciprocating movement of the focus lens is repeated across the position regarded as the in-focus state by the hill-climbing operation. For this reason, the amount of movement of the focus lens is also within the depth of focus, and the photographing screen is almost in focus (the movement speed of the focus lens is slower than a predetermined speed). Therefore, even if the user is informed that the subject is in focus after being determined to be in focus during a minute operation, there is a sense of incongruity as to whether the device has malfunctioned. This is because, when viewed from the user, information is provided by sound or display when the time has passed in the already focused state. Further, even when the AF evaluation value changes due to a slight change in the pattern of the subject, it is repeatedly determined whether or not the focus lens has moved and focused. For this reason, although the subject has not changed, information indicating that the user has been in focus many times is provided, which causes discomfort to the user.

  On the other hand, in the case of a hill-climbing operation, the focus lens is moved greatly in order to search for the peak position of the AF evaluation value from the state where the shooting screen is blurred. That is, the movement amount is larger than the minute operation. Therefore, it is not an operation in focus, but the shooting screen changes from a blurred state to a focused state, so there is no sense of incongruity even if providing information to the user that the focus has been achieved . Therefore, when the peak position is detected by the hill climbing operation, information indicating that the user is in focus is provided.

  Therefore, the information that the user is in focus is provided when the focus lens is moved in the direction of the focus position detected by the external ranging AF control and when the peak position is detected by the TV-AF operation. Thereby, it is possible to provide the user with information on an appropriate focus state without a sense of incongruity. In other words, information that can identify the in-focus state is notified before the minute operation or during the minute movement.

Here, when sound is output during shooting and recording, the output sound is recorded on a recording medium such as a tape from a sound input unit such as a microphone. If an unnecessary sound is recorded, the user feels uncomfortable at the time of reproduction. In addition, although the sound output means was used as an information provision means, it is not this limitation. For example, it is possible to allow the user to recognize the image by superimposing it on the captured image on the imaging screen of the monitor device 109 using display output means using icons, characters, or the like. In the case of providing information by display, there is no problem even if it is not limited to non-photographing recording.

Next, TV-AF control in Step 202 will be described with reference to FIG.
Step 301 indicates the start of processing.
Step 302 acquires an AF evaluation value detected from the AF signal processing 114.
In Step 303, it is determined whether or not the operation is a minute operation. If it is a minute operation, proceed to Step 304. Otherwise, go to Step 311.
In Step 304, a minute operation is performed. If it is in focus or not in focus, it is determined in which direction the focus is in focus. The operation will be described later with reference to FIG.

Step 305 is a determination as to whether or not the focus has been determined. If it is determined that the focus has been achieved, the process proceeds to Step 308 to stop the lens, and in Step 309, the AF evaluation value at the focus is held. Then, at step 310, the process shifts to the restart mode. If it is determined that the subject is not in focus, the process proceeds to Step 306.
Step 306 is a determination as to whether or not the direction of the focal point can be determined by the minute operation. If the direction of the focal point can be determined, the process proceeds to Step 307 to shift to the mountain climbing operation. If the in-focus direction cannot be determined, the AF operation is continuously performed with a minute operation.

In Step 311, it is determined whether or not the operation is a mountain climbing operation. If so, the process proceeds to Step 312, and if not, the process proceeds to Step 317.
In Step 312, the focus lens is climbed up at a predetermined speed. The detailed operation will be described later with reference to FIG.
In step 313, it is determined whether or not the AF evaluation value has exceeded the peak in the hill-climbing operation. If it is determined that the peak has been exceeded, the process proceeds to step 314. To do.

In Step 314, the focus lens is returned to the focus lens position at which the AF evaluation value is peak during the mountain climbing operation. In Step 315, it is determined whether or not the focus lens has returned to the focus lens position where the AF evaluation value is the peak. If the focus lens has returned, the process proceeds to Step 316 and proceeds to a minute operation. If not, the focus lens is continuously returned to the focus lens position where the AF evaluation value is peak during the hill-climbing operation of the focus lens.
In Step 317, it is determined whether or not it is in the restart format mode. If so, the process proceeds to Step 318, and if not, the process proceeds to Step 321.
In Step 318, the AF evaluation value held in Step 309 is compared with the latest AF evaluation value to determine whether or not the variation of the AF evaluation value is large. If the AF evaluation value has fluctuated greatly, the process proceeds to Step 320 and proceeds to a minute operation. If the AF evaluation value has not fluctuated, the process proceeds to Step 319 and the focus lens is stopped as it is.

  The process advances to Step 321 when the focus lens is moved in the direction of the in-focus position by the phase difference (phase difference signal) by the phase difference operation (phase difference drive operation by the phase difference drive mode). is there. In Step 321, it is determined whether or not the focus lens has been moved to the in-focus position due to the phase difference. When the focus lens reaches the in-focus position due to the phase difference, the process proceeds to Step 322, and the operation proceeds to a minute operation. Conversely, when the focus lens has not reached the focus position due to the phase difference, the focus lens is continuously moved to the focus position due to the phase difference.

  Although not shown in FIG. 3, when the AF evaluation value starts to decrease when the focus lens is moved to the in-focus position due to the phase difference, a process of reversing the moving direction of the focus lens is performed. A hill climbing operation is performed and the process proceeds to Step 307.

Next, the external measurement AF control in Step 203 will be described with reference to FIG.
Step 401 indicates the start of processing.
Step 402 acquires the subject distance detected by the external distance measuring unit 116, and calculates and obtains the in-focus position based on the phase difference from the subject distance.
In Step 403, it is determined whether or not it is moving in the direction of the in-focus position due to the current phase difference. If the phase difference is being moved, the movement is continued as it is. If it is not moving, the process proceeds to Step 404, and the process proceeds to a determination process for determining whether or not to switch to the operation of moving the focus lens in the direction of the in-focus position due to the phase difference.

In Step 404, a threshold value for determining whether the contrast has changed and whether the subject distance has changed is set.
In Step 405, the change of the subject is determined by contrast change, and further, the subject distance detected by the phase difference acquired in Step 402 is used to compare with the subject distance detected by the previous phase difference. Here, whether or not the contrast has changed and whether or not the subject distance has changed are determined based on whether or not the threshold set in Step 404 has been exceeded. If it is determined that there is also a contrast change and a subject distance change, the process proceeds to Step 406. However, if the condition is not met, the phase difference is not used and the process proceeds to the TV-AF control operation described above.
This Step 405 is a first-stage determination for switching whether to move the focus lens using information based on the phase difference.

Incidentally, although not described in detail, in this embodiment, the determination of the contrast change is performed by determining the maximum value of the luminance signal level of each line in the predetermined AF gate obtained from the AF signal processing 114-the maximum of the minimum value. Use the value.
Step 406 sets a focus movement amount threshold value for determining whether or not the focus lens should be moved using the in-focus position based on the phase difference. The focus movement amount threshold value is variable according to the zoom position. In the case of a rear focus lens system mainly used in a video camera like the present embodiment, the focus position for each subject distance is set in a variable manner according to the zoom position. This is because the difference changes. For example, the difference in focus position between the same 1 m to an infinite subject distance becomes wider as the focal length becomes the tele side. Therefore, for example, it is assumed that a focus movement amount threshold value is set on the telephoto side so that it can be determined that the information obtained by the phase difference is surely changing the subject distance in consideration of the focusing accuracy in the phase difference. In this case, if the same setting value is left on the wide side, it is impossible to determine that the subject distance change is not more than 1 m to infinity or more in order to obtain the same focus movement amount. This is because they will not work.

  In Step 407, the focus position based on the phase difference obtained in Step 403 is compared with the current lens position, and compared with the focus movement amount threshold value set in Step 406. If the focus movement amount is larger than the threshold value, the process proceeds to Step 408. Conversely, when the focus movement amount is smaller than the threshold value, the TV-AF control operation is continued.

  Here, the focus movement amount is compared, and the focus lens is not immediately moved in the direction of the in-focus position due to the phase difference because the AF method based on the phase difference is less accurate than the TV-AF method. . If the lens is inadvertently moved to the in-focus position due to the phase difference, hunting may occur between the TV-AF method and other AF methods, resulting in inappropriate AF operation and blurring of the image. is there.

In Step 408, it is determined whether or not the in-focus position due to the phase difference is the same as the direction in which the focus lens is moving by the TV-AF control operation with respect to the current lens position. If they are in the same direction, the phase shift operation is performed in Step 409, and the focus lens is moved in the direction of the in-focus position due to the phase difference in Step 410.
Conversely, if the directions are not the same, the TV-AF control is continued.

  As described above, Step 407 and Step 408 are determinations in the second stage for switching whether to move the focus lens using information based on the phase difference. By moving the focus lens to the in-focus position due to the phase difference and the moving direction of the focus lens in the TV-AF control, it is generated by moving in the in-focus position direction due to the phase difference. This prevents the AF operation that causes unnecessary image blur.

  The minute operation will be described with reference to FIG. The time course of the focus lens operation in the minute operation is shown. Here, the horizontal axis represents time, and the vertical axis represents the focus lens position. Also, the downwardly convex period at the top represents the vertical synchronization signal of the video signal. Here, the AF evaluation value EVA for the charge (hatched ellipse) accumulated in the CCD during the period A is taken in at time TA, and the AF evaluation value EVB for the charge (hatched ellipse) accumulated in the period B is obtained at time TB. Is taken in. At time TC, the AF evaluation values EVA and EVB are compared. If EVB> EVA, the vibration center is moved (drive amplitude = vibration amplitude + center movement amplitude), whereas if EVA> EVB, the vibration center is not moved ( Drive amplitude = vibration amplitude). Searching for a lens position where the AF evaluation value is maximized while moving is a minute operation.

  The mountain climbing operation will be described with reference to FIG. The focus lens is moved at a speed higher than a predetermined speed, and the vicinity of the peak of the AF evaluation value is found based on the AF evaluation value at that time. The figure shows the movement of the lens during the mountain climbing operation. Here, since A has decreased beyond the peak, the hill-climbing operation is terminated because there is an in-focus point, and the operation proceeds to a minute operation. On the other hand, since B is decreasing without a peak, the direction is reversed as a wrong direction. And continue climbing.

  FIG. 7 shows a hybrid AF control process performed by the camera / AF microcomputer 115 in the second embodiment of the present invention.

  In the present embodiment, the processes common to those in the first embodiment are denoted by the same reference numerals in the last two digits and the description thereof is omitted.

  In the first embodiment, in the focus adjustment control using the TV-AF method, when the hill-climbing operation is completed, information indicating that the user has focused is provided.

  However, when panning is performed on an object with a low AF evaluation value level in a low-contrast object or the like, it is impossible to determine whether the AF evaluation value has become small due to blurring of the shooting screen in TV-AF control. For this reason, there is a case where the evaluation value is once lowered even when a subject at the same distance is photographed, and thus the hill-climbing operation is started. In this case, the subject distance does not change and changes from the focused state to the focused state. Therefore, providing information to the user that the subject is in focus makes the user feel uncomfortable.

  On the tele side, when photographing a subject that is not in focus that divides the maximum close-up distance, hunting is repeated and the transition to hill-climbing operation is repeated. This is because, when climbing the peak of the AF evaluation value and reaching the peak position, the focus lens is moved to the end of the range where it can be moved, and when it moves to the reversing operation, it shifts to the minute operation. Is a factor. Then, in response to the decrease in the AF evaluation value, the hill-climbing operation is started, and the focus lens is repeatedly moved to the end of the range where the focus lens can be moved. In this case, although it is difficult to focus, the user is provided with information that the focus has been achieved when the focus lens is reversed.

  In order to avoid these, in Step 711, the AF evaluation value history is always stored and updated while the focus lens is moved by the hill-climbing operation.

  In Step 712, although not shown in detail, the focus lens position when shifting to the hill-climbing operation is stored, and compared with the peak position obtained by the hill-climbing operation when the hill-climbing operation is completed in Step 707. Then, if it is smaller than the predetermined focus movement amount threshold value, no sound output is performed. The predetermined focus movement amount threshold value here may be a value equivalent to Step 406.

  In Step 713, it is determined whether or not the AF evaluation value has a mountain shape based on the history of AF evaluation values stored in Step 712. If it is not in the shape of a mountain, do not output sound.

FIG. 8 is a block diagram illustrating a system configuration of the imaging apparatus according to the third embodiment.
In the present embodiment, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals as those in the first embodiment and the second embodiment, and the description thereof is omitted. In the first embodiment, the external distance measuring unit 116 is used. In the third embodiment, the TTL phase difference detection method (internal measurement phase difference detection method) is used.

  Reference numeral 821 denotes a half prism that performs light division for autofocus. Reference numeral 822 denotes a sub mirror, and 823 denotes an imaging lens for AF. Reference numeral 824 denotes a phase difference detection type AF sensor, and reference numeral 825 denotes an AF circuit. Reference numeral 826 denotes a zoom switch.

  The camera AF microcomputer 115 detects the shift amount and the shift direction from the output of the AF sensor 624 via the AF circuit 825.

  In the case of the imaging apparatus having such a configuration, the diaphragm 103 is actually operating during moving image shooting. Therefore, it is necessary to divide the input light by the half prism 821 before the diaphragm 103.

  In the third embodiment, the AF control algorithm described in the first embodiment can be applied by obtaining the shift amount and the shift direction of the focus state in Step 404 by using the internal measurement phase difference detection method instead of the external distance measurement method. is there.

That is, in Step 404, the shift amount and the shift direction in the focus state are acquired.
In Step 405, the subject distance change is determined from the amount of shift in the focus state.
In Step 407, the in-focus position based on the phase difference is calculated from the amount of deviation in the focus state and the direction of deviation, and is compared with the current position.
In Step 408, it is compared whether the shift direction in the focus state is the same as the direction in the TV-AF control.

  As described above, according to each of the above-described embodiments, the focusing operation can be performed at high speed and with high accuracy in the imaging apparatus having the hybrid AF function. Then, when the in-focus position is detected by the AF operation based on the phase difference and when moving to the focus lens position where the AF evaluation value is maximized by the hill-climbing operation of the TV-AF method, information that the user is in focus provide. Information provision at this time is performed by sound output or display output. As a result, it is possible to provide information on the state of focusing without causing the user to feel uncomfortable. In addition, a high-speed focusing operation can be appealed to the user.

  In addition to the focus determination performed when the shutter button is half-pressed in the conventional still image shooting mode, it is possible to easily perform the focus determination in the operation shooting mode. This allows the user to easily recognize the degree of focus.

  In the embodiments, an imaging apparatus having an imaging optical system such as a zoom lens and a focus lens has been described as an example of an optical apparatus, but the present invention is not limited to this. For example, an optical device such as a telescope or a microscope may be used.

  In the above-described embodiment, the sound output is performed after the focus lens reaches the in-focus position by the hill climbing operation or the external AF control operation. However, the focus lens is in the in-focus position when the focus lens is near the in-focus position. The sound may be output before reaching. If the focus lens arrives at the in-focus position by a minute operation, sound output is performed after a predetermined time elapses after the focus lens reaches the in-focus position by hill-climbing operation or external AF control operation. You may make it do.

1 is a configuration diagram of a video camera according to Embodiment 1. FIG. 1 is a flowchart illustrating a control flowchart according to the first embodiment. The control flowchart concerning a TV-AF system is demonstrated. The control flowchart concerning an external ranging AF system is demonstrated. It is a figure explaining minute operation. It is a figure explaining a mountain climbing operation | movement. 7 is a flowchart illustrating a control flowchart according to the second embodiment. 10 is a block diagram illustrating a circuit configuration of a video camera according to Embodiment 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Fixed 1st group lens 102 Variable magnification lens 103 Diaphragm 104 Fixed 2nd group lens 105 Focus lens 106 CCD
107 CDS / AGC
DESCRIPTION OF SYMBOLS 108 Camera signal processing circuit 109 Monitor apparatus 110 Zoom drive source 111 Focus drive source 112 AF gate 113 Recording apparatus 114 AF evaluation value processing circuit 115 Camera AF microcomputer 116 External distance measuring unit 117 Shooting recording start / end switch 118 Speaker (sound output apparatus) )

Claims (10)

After detecting the first position which is the in- focus position by the first focus detection means , the focus lens is moved to the first position at the first speed, and the second speed lower than the first speed is set. Control means for controlling to move the focus lens at a speed to detect a second position which is a focus position by the second focus detection means ;
An output means for performing output for informing the user of information that can be identified as being in focus; an imaging means for outputting an image in accordance with subject light;
Display control means for controlling the display unit to display the image,
The output means moves the focus lens to the first position at the first speed when the first focus detection means can detect the first position under the control of the control means. even after the optical device and performing the output of the information before moving the focus lens in the second speed. The first focus detection unit outputs the phase difference signal corresponding to the focus state of the focus lens by dividing and receiving the subject light, and the focus position of the focus lens based on the phase difference signal the optical device of claim 1, wherein the benzalkonium detecting the.   The output means does not output the information when the difference between the movement start position of the focus lens at the first speed and the first position does not exceed a predetermined value. The optical device according to claim 1.   The first speed is a speed when focus control is performed by moving the focus lens at a high speed, and the second speed is smaller than the first speed by moving the focus lens slightly. The optical apparatus according to claim 1, wherein the optical apparatus has a speed at which focus control is performed at a low speed and fine focus adjustment is performed. First focus detection means for detecting the focus state of the focus lens;
A second focus detection means that is less accurate than the first focus detection means;
Detecting a second position is a focus position corresponding to the output from said first focus detection means after detecting the first position is a focus position corresponding to the output from the second focus detection unit Control means for controlling so as to
An output means for performing output for informing the user of information that can be identified as being in focus; an imaging means for outputting an image in accordance with subject light;
Display control means for controlling the display unit to display the image,
The output means detects the second position by positioning the focus lens at the first position when the second focus detection means can detect the first position under the control of the control means. In order to do so, the information is output before the focus lens is moved .   The output means is a sound output means for outputting sound for notifying the user of information that can be identified as being in focus, or is superimposed on the imaging screen of the display unit and is in focus. 6. The optical apparatus according to claim 1, further comprising at least one of display output means for outputting a display for notifying the user of information that can be identified.   The optical device according to claim 1, wherein the output unit outputs the information when a moving image is captured.   The optical device according to claim 7, wherein the output unit does not output sound when the captured moving image is recorded. A control method for an optical device, comprising: an imaging unit that outputs an image according to subject light; and a display control unit that controls the display unit to display the image.
After detecting the first position which is the in- focus position by the first focus detection means , the focus lens is moved to the first position at the first speed, and the second speed lower than the first speed is set. Control to move the focus lens at a speed to detect a second position which is a focus position by the second focus detection means ;
After the focus lens is moved to the first position at the first speed when the first position is detected by the first focus detection means , the second speed is reached. A control method for an optical device, comprising: performing an output for informing a user of information that can be identified as being in focus before moving the focus lens . A control method for an optical device, comprising: an imaging unit that outputs an image according to subject light; and a display control unit that controls the display unit to display the image.
The first focus after detecting the first position, which is the focus position corresponding to the output from the second focus detection means, which is less accurate than the first focus detection means for detecting the focus state of the focus lens. Control is performed to detect the second position, which is the in- focus position according to the output from the detection means, and the first position is detected when the first focus detection means can detect the first position . Positioning the focus lens and informing the user of information that can be identified as being in focus before moving the focus lens before moving the focus lens to detect the second position A control method of an optical device, wherein control is performed so as to perform output.

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